Sensor-drainage apparatus

ABSTRACT

A sensor apparatus includes a cylindrical sensor window defining an axis oriented substantially vertically, an air nozzle positioned below the sensor window and aimed upward, and a sensor-housing-top cap positioned above the sensor window and including a sensor-housing top and a circumferential cap. The sensor-housing-top cap is a single piece. The circumferential cap includes a topside and an underside. The topside and the underside are disposed radially outward from the sensor window. The underside includes a groove having a cross-section elongated circumferentially around the axis. The cross-section of the groove curves from a lower end upwardly and outwardly to an upper end.

BACKGROUND

Autonomous vehicles include a variety of sensors. Some sensors detectinternal states of the vehicle, for example, wheel speed, wheelorientation, and engine and transmission variables. Some sensors detectthe position or orientation of the vehicle, for example, globalpositioning system (GPS) sensors; accelerometers such as piezo-electricor microelectromechanical systems (MEMS); gyroscopes such as rate, ringlaser, or fiber-optic gyroscopes; inertial measurements units (IMU); andmagnetometers. Some sensors detect the external world, for example,radar sensors, scanning laser range finders, light detection and ranging(LIDAR) devices, and image processing sensors such as cameras. A LIDARdevice detects distances to objects by emitting laser pulses andmeasuring the time of flight for the pulse to travel to the object andback. Some sensors are communications devices, for example,vehicle-to-infrastructure (V2I) or vehicle-to-vehicle (V2V) devices.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an example vehicle including a housingfor sensors.

FIG. 2 is a rear perspective view of the housing.

FIG. 3 is a rear perspective view of a sensor apparatus mounted on thehousing.

FIG. 4 is a rear perspective view of a circumferential cap of the sensorapparatus.

FIG. 5 is a cutaway perspective view of a portion of the sensorapparatus.

FIG. 6 is a cross-sectional view of the circumferential cap.

FIG. 7 is a cutaway perspective view of a portion of the sensorapparatus.

FIG. 8 is a perspective view of another example of the sensor apparatus.

FIG. 9 is a side view of the sensor apparatus of FIG. 8.

DETAILED DESCRIPTION

A sensor apparatus includes a cylindrical sensor window defining an axisoriented substantially vertically, an air nozzle positioned below thesensor window and aimed upward, and a sensor-housing-top cap positionedabove the sensor window and including a sensor-housing top and acircumferential cap. The sensor-housing-top cap is a single piece. Thecircumferential cap includes a topside and an underside. The topside andthe underside are disposed radially outward from the sensor window. Theunderside includes a groove having a cross-section elongatedcircumferentially around the axis. The cross-section of the groovecurves from a lower end upwardly and outwardly to an upper end.

The sensor-housing top may include a top surface facing a directionalong the axis, and the top surface may include a plurality of finsoriented parallel to each other. The sensor-housing top may include aside surface extending vertically from the topside of thecircumferential cap to the top surface of the sensor-housing top.

The groove may have a surface roughness Ra of at most 10 microns.

The sensor-housing-top cap may be aluminum.

The topside of the circumferential cap may include a gutter elongatedcircumferentially around the axis. The circumferential cap may include achannel extending radially outward relative to the axis from the gutter.The gutter may define a plane at an oblique angle relative to the axis.The channel may extend from a lowest point of the gutter. The groove maybe elongated circumferentially around the axis from the channel to thechannel.

The gutter may be elongated circumferentially around the axis from thechannel to the channel.

The gutter may include a gutter wall at least partially constituting thegutter, and the gutter wall may have a cross-section elongatedcircumferentially around the axis and extending diagonally outward andupward relative to the axis.

The groove may be elongated circumferentially at least 270° around theaxis.

The groove may be a first groove, and the underside of thecircumferential cap may include a second groove having a cross-sectionelongated circumferentially around the axis and extending upward fromthe first groove. The cross-section of the second groove may curve froma lower end upwardly and outwardly to an upper end. The upper end of thecross-section of the second groove may have a tangent line forming anupward-facing angle with the axis that is greater than 45°.

A diameter of the groove at the lower end of the cross-section of thegroove may be at least as great as a diameter of the sensor window.

With reference to the Figures, a sensor apparatus 32 for a vehicle 30includes a cylindrical sensor window 34 defining an axis A orientedsubstantially vertically, at least one air nozzle 36 positioned belowthe sensor window 34 and aimed upward, and a circumferential cap 38positioned above the sensor window 34 and including a topside 40 and anunderside 42. The topside 40 and the underside 42 are disposed radiallyoutward from the sensor window 34. The underside 42 includes a firstgroove 44 having a cross-section elongated circumferentially around theaxis A, and the cross-section of the first groove 44 curves from a lowerend 46 upwardly and outwardly to an upper end 48.

The sensor apparatus 32 provides a way to keep liquid off of the sensorwindow 34. The first groove 44 provides a path for liquid propelled bythe air nozzles 36 to fly off of the sensor apparatus 32 instead ofgathering, e.g., at or near a top of the sensor apparatus 32. The sensorapparatus 32 can obviate the need for other components for cleaning,e.g., a wiper. The sensor apparatus 32 achieves these benefits with asimple, low-profile design.

With reference to FIG. 1, the vehicle 30 may be any passenger orcommercial automobile such as a car, a truck, a sport utility vehicle, acrossover, a van, a minivan, a taxi, a bus, etc.

The vehicle 30 may be an autonomous vehicle. A computer can beprogrammed to operate the vehicle 30 independently of the interventionof a human driver, completely or to a lesser degree. The computer may beprogrammed to operate propulsion, brake system, steering, and/or othervehicle systems based at least in part on data received from sensorssuch as a sensor 50 described below. For the purposes of thisdisclosure, autonomous operation means the computer controls thepropulsion, brake system, and steering without input from a humandriver; semi-autonomous operation means the computer controls one or twoof the propulsion, brake system, and steering and a human drivercontrols the remainder; and nonautonomous operation means a human drivercontrols the propulsion, brake system, and steering.

The vehicle 30 includes a body 52. The vehicle 30 may be of a unibodyconstruction, in which a frame and the body 52 of the vehicle 30 are asingle component. The vehicle 30 may, alternatively, be of abody-on-frame construction, in which the frame supports the body 52 thatis a separate component from the frame. The frame and body 52 may beformed of any suitable material, for example, steel, aluminum, etc.

The body 52 includes body panels 54, 56 partially defining an exteriorof the vehicle 30. The body panels 54, 56 may present a class-A surface,e.g., a finished surface exposed to view by a customer and free ofunaesthetic blemishes and defects. The body panels 54, 56 include, e.g.,a roof 56, etc.

With reference to FIG. 2, a housing 58 for sensors including the sensor50 is attachable to the vehicle 30, e.g., to one of the body panels 54,56 of the vehicle 30, e.g., the roof 56. For example, the housing 58 maybe shaped to be attachable to the roof 56, e.g., may have a shapematching a contour of the roof 56. The housing 58 may be attached to theroof 56, which can provide the sensors with an unobstructed field ofview of an area around the vehicle 30. The housing 58 may be formed of,e.g., plastic or metal.

With reference to FIG. 3, a sensor housing 60 is supported by thehousing 58. The sensor housing 60 can be disposed on top of the housing58 at a highest point of the housing 58. The sensor housing 60 has acylindrical shape and defines the axis A. The sensor housing 60 includesa sensor-housing top 62, the sensor window 34, and a sensor-housingbottom 64. The sensor-housing top 62 is disposed directly above thesensor window 34, and the sensor-housing bottom 64 is disposed directlybelow the sensor window 34. The sensor-housing top 62 and thesensor-housing bottom 64 are vertically spaced apart by a height of thesensor window 34.

The sensor 50 is disposed inside the sensor housing 60 and is attachedto and supported by the housing 58. The sensor 50 may be designed todetect features of the outside world; for example, the sensor 50 may bea radar sensor, a scanning laser range finder, a light detection andranging (LIDAR) device, or an image processing sensor such as a camera.In particular, the sensor 50 may be a LIDAR device, e.g., a scanningLIDAR device. A LIDAR device detects distances to objects by emittinglaser pulses at a particular wavelength and measuring the time of flightfor the pulse to travel to the object and back.

The sensor window 34 is cylindrical and defines the axis A, which isoriented substantially vertically. The sensor window 34 extends aroundthe axis A. The sensor window 34 can extend fully around the axis A,i.e., 360°, or partially around the axis A. The sensor window 34 extendsalong the axis A from a bottom edge 66 to a top edge 68. The bottom edge66 contacts the sensor-housing bottom 64, and the top edge 68 contactsthe sensor-housing top 62. The sensor window 34 has a diameter. Thediameter of the sensor window 34 may be the same as the sensor-housingtop 62 and/or the sensor-housing bottom 64; in other words, the sensorwindow 34 may be flush or substantially flush with the sensor-housingtop 62 and/or the sensor-housing bottom 64. “Substantially flush” meansa seam between the sensor window 34 and the sensor-housing top 62 orsensor-housing bottom 64 does not cause turbulence in air flowing alongthe sensor window 34. At least some of the sensor window 34 istransparent with respect to whatever medium the sensor 50 is capable ofdetecting. For example, if the sensor 50 is a LIDAR device, then thesensor window 34 is transparent with respect to visible light at thewavelength generated by the sensor 50.

The sensor-housing top 62 is cylindrical in shape and extends upwardfrom the sensor window 34. The sensor-housing top 62 includes a sidesurface 72 and a top surface 70. The top surface 70 faces up, i.e., in avehicle-upward direction, i.e., axially relative to the axis A, and theside surface 72 faces horizontally outward, i.e., radially relative tothe axis A. The top edge 68 of the sensor window 34 is spaced from thetop surface 70 by a height of the side surface 72.

The top surface 70 includes a plurality of fins 74. The fins 74 extendupward from the rest of the top surface 70, and the fins 74 are orientedparallel to each other. The fins 74 can be oriented along avehicle-forward direction. The fins 74 are thermally conductive, i.e.,have a high thermal conductivity, e.g., a thermal conductivity equal toat least 15 watts per meter-Kelvin (W/(m K)), e.g., greater than 100W/(m K), at 25° C. For example, the fins 74 may be aluminum.

The sensor apparatus 32 includes a plurality of the air nozzles 36. Theair nozzles 36 are mounted on the housing 58. The air nozzles 36 arepositioned below the sensor window 34 and are arranged circumferentiallyaround the sensor housing 60. The air nozzles 36 are aimed upward, e.g.,aimed in a direction parallel to the axis A. The air nozzles 36 canreceive airflow from, e.g., a compressor or blower (not shown).

The circumferential cap 38 is positioned above the sensor window 34 andfixed relative to the sensor window 34. The circumferential cap 38 isattached to the sensor-housing top 62 and extends circumferentiallyaround the sensor-housing top 62.

With reference to FIG. 4, the circumferential cap 38 includes an innersurface 76. The inner surface 76 faces radially inward and extendscircumferentially around the axis A. The circumferential cap 38 contactsthe sensor-housing top 62 continuously along a circumference via theinner surface 76. The inner surface 76 has a cylindrical shape with adiameter approximately equal to the diameter of the sensor-housing top62. For example, the diameter of the inner surface 76 when thecircumferential cap 38 is unstressed can be slightly smaller than thediameter of the sensor-housing top 62, and the circumferential cap 38can be attached to the sensor-housing top 62 with a press fit. Foranother example, the diameter of the inner surface 76 can be equal to orslightly larger than the diameter of the sensor-housing top 62, and thecircumferential cap 38 can be attached to the sensor-housing top 62 withadhesive.

The circumferential cap 38 includes at least one, e.g., two, braces 78.Each brace 78 is elongated between two adjacent fins 74 and is parallelto the fins 74. Ends of the braces 78 are connected to the topside 40 ofthe circumferential cap 38. The braces 78 can support the rest of thecircumferential cap 38 and prevent the circumferential cap 38 fromsliding down the sensor-housing top 62. The circumferential cap 38leaves the top surface 70 of the sensor-housing top 62 exposed exceptfor the braces 78.

The circumferential cap 38 is a thermally conductive polymer, i.e., apolymer with high thermal conductivity for a polymer, e.g., a thermalconductivity equal to at least 1.0 watts per meter-Kelvin (W/(m K)),e.g., greater than 5 W/(m K), at 25° C.

With reference to FIGS. 5 and 6, the circumferential cap 38 includes thetopside 40 and the underside 42. The circumferential cap 38 has aconstant cross-section that is elongated circumferentially around theaxis A, e.g., elongated circumferentially more than 270° around the axisA. The circumferential cap 38 includes a channel 80 (described below),and the constant cross-section of the circumferential cap 38 iselongated circumferentially from the channel 80 to the channel 80. Thecross-section of the circumferential cap 38 includes the inner surface76, the topside 40, and the underside 42. The topside 40 is the portionof the cross-section of the circumferential cap 38 that is projectablestraight upward, i.e., is visible from a point of view looking straightdownward at the circumferential cap 38. The underside 42 is the portionof the cross-section of the circumferential cap 38 that is projectablestraight downward, i.e., is visible from a point of view lookingstraight upward at the circumferential cap 38. The topside 40 and theunderside 42 are disposed radially outward from the sensor window 34.

The underside 42 includes the first groove 44. The first groove 44 has across-section that is elongated circumferentially around the axis A,e.g., elongated circumferentially more than 270° around the axis A,e.g., elongated circumferentially from the channel 80 to the channel 80.The cross-section of the first groove 44 curves from the lower end 46upwardly and outwardly to the upper end 48. The lower end 46 has atangent line oriented parallel to the axis A, and the upper end 48 has atangent line oriented diagonally outward and upward relative to the axisA. The tangent line of the upper end 48 of the first groove 44 forms anupward-facing angle θ₁ of less than 60°, e.g., approximately 50°, withthe axis A, as shown in FIG. 6. The diameter of the first groove 44 atthe upper end 48 end of the cross-section is greater than the diameterof the first groove 44 at the lower end 46 of the cross-section. Thediameter of the first groove 44 at the lower end 46 of the cross-sectionis at least as great as the diameter of the sensor window 34.

The underside 42 of the circumferential cap 38 includes a second groove82 extending upward from the first groove 44. The second groove 82 has across-section that is elongated circumferentially around the axis A,e.g., elongated circumferentially more than 270° around the axis A,e.g., elongated circumferentially from the channel 80 to the channel 80.The cross-section of the second groove 82 curves from a lower end 84upwardly and outwardly to an upper end 86. A tangent line of the upperend 86 of the second groove 82 forms an upward-facing angle θ₂ that isgreater than 45°, e.g., approximately 65°, with the axis A, as shown inFIG. 6. The diameter of the second groove 82 at the upper end 86 of thecross-section is greater than the diameter of the second groove 82 atthe lower end 84 of the cross-section. The diameter of the second groove82 at the lower end 84 of the cross-section is equal to the diameter ofthe first groove 44 at the upper end 48 of the cross-section of thefirst groove 44.

The topside 40 of the circumferential cap 38 includes a gutter 88. Thegutter 88 is elongated circumferentially around the axis A, e.g.,elongated circumferentially more than 270° around the axis A, e.g.,elongated circumferentially from the channel 80 to the channel 80. Thegutter 88 includes a gutter wall 90 at least partially constituting thegutter 88, and the gutter wall 90 has a cross-section elongatedcircumferentially around the axis A and extending diagonally outward andupward relative to the axis A. The gutter wall 90 forms an upward-facingangle φ that is greater than 45°, e.g., approximately 65°, with the axisA, as shown in FIG. 6.

With reference to FIG. 7, the circumferential cap 38 includes thechannel 80. The extends radially outward relative to the axis A from thegutter 88. The channel 80 is lower than an upper height of the gutter88, i.e., lower than a top of the gutter wall 90. The channel 80 can bepositioned at a rearwardmost position on the circumferential cap 38, asshown in FIG. 3.

In operation, liquid may land on the sensor window 34. The liquid may bewater, e.g., precipitation such as rain, or may be washer fluid from,e.g., a cleaning system of the vehicle 30. The airflow from the airnozzles 36 pushes the liquid upward to the first groove 44. The shape ofthe cross-section of the first groove 44 causes the upward-moving liquidto fly off of the sensor apparatus 32; in other words, the momentum ofthe liquid causes the liquid to slide from the lower end 46 to the upperend 48 of the first groove 44 and then off of the upper end 48 at theangle of the upper end 48. Liquid that lands on the top surface 70 ofthe sensor-housing top 62 is caught by the gutter 88 as the liquid flowsoff of the top surface 70, and the gutter 88 carries the liquid to thechannel 80, where the liquid exits rearward from the sensor apparatus 32without contacting the sensor window 34.

In operation, the sensor 50 generates heat. Much of the heat generatedby the sensor 50 is transmitted to the sensor-housing top 62. Thesensor-housing top 62 radiates heat outward through the fins 74 andtransmits heat to the circumferential cap 38. The circumferential cap 38can transfer heat to liquid flowing through the gutter 88, which allowsthe heat to exit the sensor apparatus 32 along with the liquid. Theflowing liquid increases the rate of heat transfer through thecircumferential cap 38 compared with not having a replenishing supply ofliquid to transfer heat to.

With reference to FIGS. 8 and 9, in another example of the sensorapparatus 32, the sensor apparatus 32 includes a sensor-housing-top cap92. The sensor-housing-top cap 92 is positioned above the sensor window34 and contacts the sensor window 34 at the top edge 68. Thesensor-housing-top cap 92 includes the sensor-housing top 62 and thecircumferential cap 38.

The sensor-housing-top cap 92 is a single piece, i.e., made of a single,uniform piece of material with no seams, joints, fasteners, or adhesivesholding it together. For example, the sensor-housing-top cap 92 isaluminum, which has a sufficiently high thermal conductivity and can beeasily shaped. For example, the sensor-housing-top cap 92 can be formedby casting and then machining to the shape shown in FIGS. 8 and 9.Making the sensor-housing-top cap 92 a single piece makes manufacturingand assembly simpler, makes meeting tolerances easier, and provides asmoother path for liquid traveling upward from the sensor window 34 tothe circumferential cap 38.

The sensor-housing top 62 is cylindrical in shape and includes the sidesurface 72 and the top surface 70. The top surface 70 faces up, i.e., ina vehicle-upward direction, i.e., in a direction along the axis A, i.e.,axially relative to the axis A. The side surface 72 faces horizontallyoutward, i.e., radially relative to the axis A. In this example of thesensor apparatus 32, the side surface 72 extends vertically from thetopside 40 of the circumferential cap 38 to the top surface 70 of thesensor-housing top 62, rather than extending from the sensor window 34as described above.

In this example of the sensor apparatus 32, the circumferential cap 38lacks the inner surface 76 and is unitary with the sensor-housing top 62rather than being attached to the sensor-housing top 62 by, e.g., apress fit. The circumferential cap 38 includes the topside 40 and theunderside 42 as described above. The circumferential cap 38 has aconstant cross-section that is elongated circumferentially around theaxis A, e.g., from the channel 80 to the channel 80. The cross-sectionof the circumferential cap 38 is elongated following a path that is in aplane that intersects the axis A at an oblique angle, i.e., an angleneither orthogonal nor parallel to the axis A. The path followed by thecross-section of the circumferential cap 38 is elliptical. The gutter88, the first groove 44, and the second groove 82 all follow the path inthe plane and thus define the plane or define a parallel plane formingthe same oblique angle relative to the axis. The channel 80 extends froma lowest point of the cross-section, i.e., a lowest point of the gutter88, the first groove 44, and the second groove 82. The tilt of thegutter 88 helps liquid that is in the gutter 88 exit via the channel 80.

The underside 42, including the first groove 44 and the second groove82, have a surface roughness Ra of at most 10 microns. The surfaceroughness Ra is the arithmetical mean of the absolute values ofdeviations from a centerline of a surface profile of the surface ofinterest, i.e., Ra=(Σ_(i=1) ^(n)|y_(i)|)/n, in which i is an index ofmeasurements, n is the number of measurements, and y_(i) is thedeviation of measurement i from the centerline of the surface. The lowroughness of the underside 42 helps liquid that is traveling upward fromthe sensor window 34 to fly off of the underside 42 instead of gatheringat the bottom of the circumferential cap 38. For example, the underside42 can be machined aluminum.

The disclosure has been described in an illustrative manner, and it isto be understood that the terminology which has been used is intended tobe in the nature of words of description rather than of limitation.“Substantially” as used herein means that a dimension, time duration,shape, or other adjective may vary slightly from what is described dueto physical imperfections, power interruptions, variations in machiningor other manufacturing, etc. The adjectives “first” and “second” areused throughout this document as identifiers and are not intended tosignify importance, order, or quantity. Many modifications andvariations of the present disclosure are possible in light of the aboveteachings, and the disclosure may be practiced otherwise than asspecifically described.

What is claimed is:
 1. A sensor apparatus comprising: a cylindricalsensor window defining an axis oriented substantially vertically; an airnozzle positioned below the sensor window and aimed upward; and asensor-housing-top cap positioned above the sensor window and includinga sensor-housing top and a circumferential cap; wherein thesensor-housing-top cap is a single piece; the circumferential capincludes a topside and an underside, the topside and the undersidedisposed radially outward from the sensor window, the undersideincluding a groove having a cross-section elongated circumferentiallyaround the axis, the cross-section of the groove curving from a lowerend upwardly and outwardly to an upper end.
 2. The sensor apparatus ofclaim 1, wherein the sensor-housing top includes a top surface facing adirection along the axis, and the top surface includes a plurality offins oriented parallel to each other.
 3. The sensor apparatus of claim2, wherein the sensor-housing top includes a side surface extendingvertically from the topside of the circumferential cap to the topsurface of the sensor-housing top.
 4. The sensor apparatus of claim 1,wherein the groove has a surface roughness Ra of at most 10 microns. 5.The sensor apparatus of claim 1, wherein the sensor-housing-top cap isaluminum.
 6. The sensor apparatus of claim 1, wherein the topside of thecircumferential cap includes a gutter elongated circumferentially aroundthe axis.
 7. The sensor apparatus of claim 6, wherein thecircumferential cap includes a channel extending radially outwardrelative to the axis from the gutter.
 8. The sensor apparatus of claim7, wherein the gutter defines a plane at an oblique angle relative tothe axis.
 9. The sensor apparatus of claim 8, wherein the channelextends from a lowest point of the gutter.
 10. The sensor apparatus ofclaim 9, wherein the groove is elongated circumferentially around theaxis from the channel to the channel.
 11. The sensor apparatus of claim9, wherein the gutter is elongated circumferentially around the axisfrom the channel to the channel.
 12. The sensor apparatus of claim 6,wherein the gutter includes a gutter wall at least partiallyconstituting the gutter, and the gutter wall has a cross-sectionelongated circumferentially around the axis and extending diagonallyoutward and upward relative to the axis.
 13. The sensor apparatus ofclaim 1, wherein the groove is elongated circumferentially at least 270°around the axis.
 14. The sensor apparatus of claim 1, wherein the grooveis a first groove, the underside of the circumferential cap includes asecond groove having a cross-section elongated circumferentially aroundthe axis and extending upward from the first groove.
 15. The sensorapparatus of claim 14, wherein the cross-section of the second groovecurves from a lower end upwardly and outwardly to an upper end.
 16. Thesensor apparatus of claim 15, wherein the upper end of the cross-sectionof the second groove has a tangent line forming an upward-facing anglewith the axis that is greater than 45°.
 17. The sensor apparatus ofclaim 1, wherein a diameter of the groove at the lower end of thecross-section of the groove is at least as great as a diameter of thesensor window.